If you are on a budget, I would do the body lift and a set of coil spacers, or even leveling coils. If you're not on a tight duget, then skip the Tough Country and go straight to a SkyJacker kit. Skyjack is much better quality from EVERYTHING I've heard.
I don't remember if it is Tough Country, or Rough Country, or both, that have the drop "plate" not drop "bracket". The drop plate is a poor design, and if you have a D35 front end, then you run a very good chance of punching a hole in your differential becuase of the plate.
By doing the 3" body lift and coil spacers, you will essentially get 4-5" of lift in the front, and 3" in the back, which would be better than just a 4" lift. The tires have clearance issues in the front, so only lifting the rear 3" should not be a problem at all out back, and in the front you will actually have 4-5" of lift (combining the body lift and leveling).
That is my two cents worth, and what I would do if I were you.